A particular application of the present invention is directed to reducing post-operative trauma following surgery of the parathyroid glands, thyroid gland or adjacent structures in the neck. Calcium homeostasis (i.e. the maintenance of a normal level of calcium in the serum component of the blood) is an important requirement of living organisms. Normal calcium levels are necessary for coagulation of blood, normal bone development, proper function of the nervous, muscular, cardiovascular and endocrine systems and for many cellular processes fundamental to normal function of all cells in the human body.
Calcium homeostasis is controlled through complex and dynamic interactions of bone in the skeleton (serving as a reservoir of calcium), intestines (where dietary Calcium is absorbed into the blood), the kidneys (which secrete 1,25 dihydroxyvitamin D causing calcium absorption in intestines and which excretes calcium into urine in varying amounts), parathyroid hormone (secreted by the parathyroid glands in the neck), and the serum component of blood (serving as transport medium among these organs). Through complex and dynamic interactions of these organs, the human body continually tries to maintain a normal level of serum calcium (8.5-11 mg/100 ml serum).
Parathyroid hormone maintains normal levels of serum calcium by means of two effects. It mobilizes calcium from bone into serum and inhibits excretion of calcium from kidneys into urine. If there is an insufficient amount of parathyroid hormone (hypoparathyroidism), the level of serum calcium decreases (hypocalcemia). Hypocalcemia can be mild and asymoptomatic or severe and life threatening producing paresthesias, tetany, carpopedal spasm, laryngospasm, convulsions, cardiac arrhythmias and death.
It is known that after surgery of the parathyroid glands, thyroid gland or adjacent structures in the neck, hypocalcemia can occur. Hypocalcemia is classified as temporary or permanent. Ischemia (decrease in oxygen supplied due to impairment of blood flow) of the parathyroid glands is the most commonly accepted cause of temporary hypoparathyroidism. Ischemia may also arise from temporary vascular spasm of the parathyroid blood vessels which results from surgical trauma or permanent impairment of blood flow through the parathyroid vessels owing to surgical trauma, with parathyroid function returning as neovascularization is established after surgery.
The appearance of hypocalcemia or its symptoms requires the patient to remain in the hospital until the hypocalcemia or its symptoms are addressed. The lengthened hospital stay increases costs and reduces the efficiency of the hospital and the attending physicians. Therefore, there is a need to safely reduce hypocalcemia induced during surgical procedures involving the parathyroid glands, the thyroid gland or adjacent structures in the neck. In addition, the general need exists for reducing surgery induced trauma on tissues exposed during open surgery.